This paper reports on new developments of advanced CD AFM probes after the prior introduction of "trident probes" in SPIE Advanced Lithography 2007 [1]. Trident probes, having sharpened extensions in the tip apex region, make possible bottom CD measurements within a few nanometers of the feature bottom corner; an area where other CD probes have difficulties due to tip shape limitations. Moreover, new metrology applications of trident probes have been developed for novel devices such as FinFET and vertical read/write hard disk heads. For ever smaller technology nodes, new probes evolved from the design of the trident probe. For example, the number of sharpened tip flares was reduced from three (trident) to two (bi-pod) to prevent possible interference of the third leg in the slow scan direction, as shown in Figure 3. Maintaining tip lateral stiffness as the tip size shrinks to less than 30 nm is vital for successful scanning. Consequently, a significant recent improvement is the change of probe shank cross-sectional geometry in order to maintain tip vertical aspect ratio of 1:5 (and lateral stiffness > 1 N/m). Finally, modifications of probe substrate are proposed and evaluated for current and new CD AFM systems. Hydrophobic, self-assembled monolayer (SAM) coatings were applied on CD probes to reduced tip "pull-away" distance1 during CD AFM scanning. Test results show that the pull away distance can be reduced more than 5 times on average (in some cases, by a factor of 15). Consequently, use of hydrophobic SAM coatings on CD probes mitigates pull-away distance thus allowing narrow trench CD measurements. We discuss limitations of prior CD AFM probes and design considerations of new CD probes. The characterization of first prototypes and evaluation of scan performance are presented in this work.

Ensemble lentille objective, comportant des premiere, deuxieme et troisieme pieces polaires, qui sont chacune sensiblement a symetrie de revolution. Les premiere, deuxieme et troisieme pieces polaires sont disposees d'un meme cote d'un plan objet. Une extremite de la premiere piece polaire est separee d'une extremite de la deuxieme piece polaire pour former un premier espace, et une extremite de la troisieme piece polaire est separee d'une extremite de la deuxieme piece polaire pour former un deuxieme espace. Une premiere bobine d'excitation cree un champ magnetique de focalisation dans le premier espace, et une deuxieme bobine d'excitation cree un champ magnetique de compensation dans le deuxieme espace. Des premiere et deuxieme alimentations alimentent respectivement en courant les premiere et deuxieme bobines d'excitation. Un flux magnetique cree dans la deuxieme piece polaire est oriente dans la meme direction que le flux magnetique cree dans la deuxieme piece polaire.

Electron projection lithography (EPL) is one of the leading candidates for next-generation lithography at the 65-nm lithography node, particularly for contact levels. EPL has traditionally employed either an open stencil mask with a single patterned (perforated) scattering layer or a continuous membrane mask with a patterned scattering layer supported by an un-perforated membrane. This article reports on an experimental study of a type of EPL mask developed by Team Nanotec that employs a continuous ultrathin membrane (UTM) comprised of a trilayer of carbon, silicon nitride, and carbon. These UTM masks combine all of the benefits of continuous membrane masks with the higher energy throughput (and the smaller chromatic aberration) of an open stencil mask.

Electron Projection Lithography ( EPL) is a leading candidate for the sub-65 nm lithography regime (1),(2). The development of a low-distortion mask is critical to the success of EPL. EPL has traditionally used either a stencil format mask with a single scatterer layer having the pattern represented by voids in the membrane (3), or a continuous membrane format mask with a patterned scatterer layer supported by an unperforated membrane(4).

Electron projection lithography (EPL) is one of the leading candidates for the sub-65 nm lithography node. The development of a low-distortion mask is critical to the success of EPL. This article proposes and analyzes two new EPL mask formats described as a “corrugated-continuous membrane mask” and a “carbon-continuous membrane mask.” Novel process flows for the manufacture of these masks have been developed at Team Nanotec GmbH. Resonant frequency stress measurements of the ultrathin membrane bilayers were completed and subsequently used in the finite element simulation of the mask fabrication and pattern transfer. The new mask types have the benefits of the lower distortions of a typical continuous membrane mask, but maintain the advantage of the higher throughput stencil format because of the ultrathin films. In addition, the proposed masks remove the need for pattern splitting typically used with complementary systems.